Police have released CCTV images of three men they want to trace after a 33-year-old man was left outside a hospital with a serious stab wound.

Westley Murray is in an induced coma after he was pulled out of a car and left at Queens Hospital's Accident and Emergency ward, in Romford, east London, shortly after 1am on Sunday.

CCTV footage shows a dark-coloured Toyota Prius arrive at the ward's entrance before the driver stops outside the doorway and goes inside.

He returns with two other men, who police believe he asked for help.

The driver then helps the men unload Mr Murray from the passenger seat of the car and put him in a wheelchair.

As the two men push the wheelchair into the hospital, the car drives off.

Scotland Yard believes the vehicle may have been a taxi because a Transport for London sticker was displayed on the back window.

Mr Murray remains in an induced coma at the hospital, having suffered a serious stab wound to the abdomen.

Police are appealing for information to trace the driver of the car and anyone who may have seen Mr Murray on Saturday evening.

They also want to hear from either of the two men who helped the driver get Mr Murray inside the hospital.

Detective Sergeant Rob Baxter, from Havering CID, said: "We are trying to piece together Westley's movements in the hours leading to him being stabbed.

"If anyone knows where he was and who saw him, please let us know. You may have vital information about how Westley came to receive his injuries.

"Also I'd ask the driver of the car and the two men who helped at the hospital to get in touch with us. You must have information that can help us track down who was responsible for the attack on Westley. You took action that may have saved Westley's life but he still needs your help.

"We have found no obvious motive for the attack on Westley."

Anyone with any information is asked to call 01708 779 216 or contact Crimestoppers anonymously on 0800 555 111.